Nanometre facts for kids

Quick facts for kids nanometre
One nanometric carbon nanotube, visualized using a scanning tunnelling microscope
General information
Unit system	SI
Unit of	length
Symbol	nm
Conversions
1 nm in ...	... is equal to ...
SI units	1×10−9 m    1×103 pm
Natural units	6.1877×1025 ℓP  18.897 a0
imperial/US units	3.9370×10−8 in

Different lengths across the electromagnetic spectrum, showing how the nanometre measures tiny structures and light waves.

A nanometre (spelled nanometer in American English; symbol: nm) is an extremely tiny unit of length in the metric system. One nanometre equals one billionth of a metre (1/1,000,000,000 m). To picture this, if a single marble were one nanometre wide, then planet Earth would be about one metre wide.

Scientists use nanometres to measure tiny objects like atoms, molecules, and the parts inside living cells. It is also the main unit used to measure the wavelengths of visible light and to build modern computer microchips.

What Is a Nanometre and How Small Is It?

To understand the nanometre, it helps to compare it to everyday metric units. A metre is about the length of a guitar. A millimetre is one-thousandth of a metre, roughly the thickness of a credit card.

A micrometre (often called a micron) is one-thousandth of a millimetre. It measures items like red blood cells and dust specks. A nanometre is one-thousandth of a micrometre.

Scientific Notation and Scale Comparison

In scientific notation, one nanometre is written as 1 × 10⁻⁹ metres.

Here is how the nanometre compares to familiar items:

• A single sheet of paper is about 100,000 nm thick.
• A strand of human hair is roughly 80,000 to 100,000 nm wide.
• A single red blood cell measures around 7,000 nm across.
• A typical virus ranges between 20 nm and 400 nm across.
• A strand of human DNA is about 2.5 nm wide.
• A single water molecule is roughly 0.28 nm across.
• A basic atom, like helium, has a diameter of about 0.06 nm.

Name Origin and Metric History

The word "nanometre" combines two ancient terms. The prefix nano- comes from the Ancient Greek word nanos, which means "dwarf" or "little old man." The base word metre comes from the Greek word metron, which means "measure."

Before modern international agreements standardized the metric system, scientists called this unit the "millimicron" or "millimicrometre." In older scientific books, you might see it written as mμ. In 1960, the International System of Units (SI) officially adopted the standard name nanometre and the symbol nm.

Why the Nanometre Matters in Daily Life

Nanometres may seem impossibly tiny, but they are crucial to how nature and technology work.

Light Waves and the Colors We See

Light travels in waves, and the distance between wave crests is called a wavelength. The light that human eyes can see is called visible light.

Scientists measure visible light wavelengths in nanometres:

• Violet light has short, high-energy waves around 380 to 450 nm.
• Blue light has wavelengths between 450 and 495 nm.
• Green light ranges from 495 to 570 nm.
• Yellow light spans 570 to 590 nm.
• Orange light spans 590 to 620 nm.
• Red light has long wavelengths between 620 and 750 nm.

Light waves shorter than violet are called ultraviolet (UV) light, which ranges from 10 to 400 nm. Waves longer than red light enter the infrared range, starting above 750 nm.

How Computer Processors Use Nanometres

Computers, gaming consoles, and smartphones rely on microchips packed with billions of microscopic switches called transistors. Engineers build these switches using measurements on the nanometre scale.

In the 1990s, computer chips had features measuring hundreds of nanometres across. Modern manufacturing techniques build transistors with features only a few nanometres wide. Smaller features let engineers pack more transistors onto a single chip. This makes computers faster, smaller, and more energy-efficient.

Nanotechnology and New Materials

Nanotechnology is the science of building and manipulating materials at the scale of 1 to 100 nanometres. When materials are shrunk to the nanoscale, their chemical and physical rules often change dramatically.

Unique Properties at the Nanoscale

At the nanoscale, materials behave differently than they do in bulk form:

• Surface Area: Nanoparticles have a massive surface area compared to their volume. This makes chemical reactions happen much faster.
• Color Changes: Bulk gold is shiny and yellow, but tiny gold nanoparticles appear ruby red or purple because of how they bend light.
• Strength: Carbon atoms arranged in tiny tubes, called carbon nanotubes, are only a few nanometres wide but are much stronger than steel while remaining very light.

Everyday Uses of Nanomaterials

Nanotechnology is used in many common products:

• Clear Sunscreen: Sunscreens use nanoparticles of zinc oxide or titanium dioxide. They block harmful UV rays while appearing completely transparent on the skin.
• Stain-Resistant Fabrics: Clothing fibers coated with tiny nanoscale whiskers repel liquids and dirt.
• Scratch-Proof Coatings: Eyeglass lenses and car paints use nanoscale ceramic particles to resist scratches.
• Lightweight Sports Gear: Tennis rackets and bicycles use carbon nanotubes for extra strength without adding weight.

Measuring on the Nanoscale

Standard optical microscopes use visible light to view objects. Because light waves are hundreds of nanometres wide, they cannot focus on anything smaller than roughly 200 nm.

Scientists use specialized tools to view and manipulate atoms and molecules at the nanometre scale:

• Electron Microscopes: These instruments use beams of electrons instead of light. Because electron waves are much shorter than light waves, these microscopes can magnify objects up to several million times.
• Scanning Probe Microscopes: These tools use an ultra-fine physical tip that moves across a surface, feeling the atomic bumps like a record player needle.
• Atomic Force Microscopes: These devices measure the tiny forces between the probe tip and the sample, creating detailed 3D maps of individual molecules.

Related Units of Measurement

The nanometre belongs to the SI family of length units. It connects directly to other metric measurements:

• Micrometre (µm): 1 µm = 1,000 nm (used for bacteria and cells).
• Nanometre (nm): 1 nm = 1,000 picometres.
• Picometre (pm): 1 pm = 0.001 nm (used for measuring atomic nuclei).
• Ångström (Å): An older non-SI unit equal to 0.1 nm (often used in chemistry to describe atomic bonds).

See also

In Spanish: Nanómetro para niños